If you need to change gears as you approach a turn, you should do so:

Answer: C — Before the turn

When approaching a turn while riding a motorcycle, it is safest to change gears before the turn. This allows you to focus your full attention on navigating the turn itself without the added complexity of gear changes. Changing gears before the turn ensures that you are in the appropriate gear for the speed and conditions of the turn, helping you maintain control and stability throughout the maneuver. It is important to plan ahead and be in the correct gear before entering the turn to make the riding experience smoother and safer.